Fig. 2
From: Sub-Hz fundamental, sub-kHz integral linewidth self-injection locked 780 nm hybrid integrated laser
SIL laser characterization. (a) Laser frequency noise measurements with fiber MZI optical frequency discriminator (OFD) and second harmonic generation (SHG) frequency-doubled cavity-stabilized fiber frequency comb for beat-note measurements. (b) OSA free running vs. single mode with 36 dB side-mode-suppression ratio (SMSR). (B) Frequency noise for the SIL laser with data stitched between comb beat note and OFD data. Spurs at multiples of 11.3 MHz correspond to the free-spectral range of the OFD MZI and do not contribute to the integral linewidth calculation.
